保持OnTouchListener订阅运动事件，即使是那些在视图外启动的事件

Question

我正在尝试实现一个像水果忍者或割绳子的cut action。

我的视图应该拦截这些cuts(让我们称之为swipes)事件。我设置了一个简单的onSwipeTouchListener，它工作得很好，但只有当Motionevent.ACTION_DOWN被制作(滑动开始)在视图内，这是可悲的!

我不知道为什么系统不调度视图内部的ACTION_MOVE事件，除非ACTION_DOWN也在视图内部。

非常感谢!

Answer 1

我所能做的就是强制调度覆盖dispatchTouchEvent(MotionEvent)方法从活动:

@Override
public boolean dispatchTouchEvent(MotionEvent ev) {
    dim = new Dimensions();
    dim.set(ev);
    super.dispatchTouchEvent(ev);
    if(ev.getAction()==MotionEvent.ACTION_MOVE)
    {
        if(dim.isInside(sg)){
            if(!ActionDownPassed) {
                ev.setAction(MotionEvent.ACTION_DOWN);
                ActionDownPassed = true;
            }
        }else if(ActionDownPassed){
            ev.setAction(MotionEvent.ACTION_UP);
        }
        sg.dispatchTouchEvent(ev);
    }
    if(ev.getAction()==MotionEvent.ACTION_UP) ActionDownPassed = false;
    return false;
}

它工作，但是我不认为这是一个好主意。

PS: Dimensions类:

public class Dimensions {
public int width;
public int height;
public Dimensions() {}
public Dimensions(int w, int h) {
    width = w;
    height = h;
}
public Dimensions(Dimensions p) {
    this.width = p.width;
    this.height = p.height;
}
public final void set(int w, int h) {
    width = w;
    height = h;
}
public final void set(Dimensions d) {
    this.width = d.width;
    this.height = d.height;
}
public final void set(MotionEvent e){
    this.width = (int) e.getX();
    this.height = (int) e.getY();
}
public final boolean equals(int w, int h) {
    return this.width == w && this.height == h;
}
public final boolean equals(Object o) {
    return o instanceof Dimensions && (o == this || equals(((Dimensions)o).width, ((Dimensions)o).height));
}
public boolean isInside(View v){
    int[] a = new int[2] ;
    v.getLocationOnScreen(a);
    int w = v.getWidth();
    int h = v.getHeight();
    if(   a[0] <= this.width
            && this.width <= (a[0] + w)
        && a[1] <= this.height
            && this.height <= (a[1] + h) )
        return true;
    else return false;
}

}